There’s at least a decent chance that Kelvin Herrera isn’t even on the Kansas City Royals roster in 2018. Under the assumption he doesn’t get traded, we’re going to evaluate him, because he’s a key cog on this team.
Herrera had what I would consider to be his worst big-league season in 2017. His BB/9 rate returned to the 3’s where it had been for most of his career. Herrera’s BB/9 rate in 2016 was in the 1’s, which probably had something to do with his success. His HR/FB (HR/Fly Ball) rate was the highest it had been in any season since 2013.
I can’t help but wonder how much of Herrera’s decline in 2017 was due to fatigue. Yes, they made him the closer, but Herrera didn’t find much success regardless of his role. Herrera had logged 211 2/3 innings pitched over the previous three seasons, which is a lot for a reliever who makes his living on throwing the baseball hard. That number doesn’t include his 28 2/3 innings pitched in the playoffs in 2014 and 2015.
Herrera is a max-effort guy, and it can be reasonably believed that fatigue had begun to set in this season. Having not made the playoffs in 2016 and 2017, combined with his lowest innings total since 2013, should allow Herrera to rest up a bit this offseason.
How much better will Herrera be?
For that reason, I can’t expect Kelvin Herrera to be as bad in 2018 as he was in 2017. Do I expect him to be as dominant as he was in 2014? No. I don’t even expect him to be as good as he was in 2016. But I do expect him to be better than 2017, for sure.
Herrera had a couple of recurring forearm issues that hampered him throughout 2017, but his velocity didn’t change (97.8 MPH average in 2016 and 2017). And he was actually throwing his off-speed pitches harder than in years past. (Both his changeup and slider velocity were nearly career-highs.) He induced more ground balls than in any season since 2014. He also induced fewer line-drives than in any season since 2012.
In my opinion, the amount of rest Herrera will get this offseason, combined with the motivation he’ll have heading into a contract year, sets things up nicely for his 2018. Herrera will be 28 years old next season, and I expect he’ll pitch his way into a nice payday next winter.